The present invention generally relates to a fluid flow control assembly and, more particularly, to the fluid flow control assembly for use as a fluid outlet grille structure of a fan-forced space heater such as, for example, a fan-forced oil heater, a fan-forced gas heater or a fan-forced electric heater, or an air-conditioner.
A device for controlling respective flows of the two incoming fluid streams is disclosed in, for example, the Japanese Laid-open Patent Publication No. 57-166441 published Oct. 13, 1982, and reproduced in FIG. 1 of the accompanying drawings in top sectional representation. As shown in FIG. 1, the prior art device comprises a generally rectangular, open-sided frame structure having two divided fluid passages each communicated at one and with a source of incoming fluid and at the opposite end delimited by a pair of curved guide walls arranged so as to outwardly diverge away from each other. The frame structure has a pair of constricted nozzle openings defined in the respective fluid passages upstream of and behind the respective pairs of the curved guide walls with respect to the direction of flow of fluid streams through the respective nozzle openings.
A pair of constricting plates arranged in the frame structure for each nozzle opening and defining the respective nozzle opening therebetween define spaced apart control windows R1 and R2, or L1 and L2, in cooperation with upstream ends of the curved guide walls, which windows are in communication with respective chambers defined exteriorly of and on respective sides of the associated fluid passage. One of the paired chambers for each fluid passage is provided with an electromagnetic valve SV1 or SV2 for controlling the flow of fluid into the adjacent fluid passage through the associated control window R1 or L2, so that the fluid streams ready to emerge outwardly from the respective fluid passages can be deflected rightwards or leftwards, as viewed in FIG. 1, by controlling the flow of fluid into the fluid passages through the associated control windows R1 and L2.
With the prior art device of the above described construction, it has been found that the flow of each fluid stream is deflected in the form of a beam, i.e., having a reduced flow width, as shown by P and Q and, accordingly, the draft of fluid as a whole tends to have such a strong directivity that only a limited region of space can receive the draft of fluid.